Most toilet installations include a tank mounted above the toilet bowl. A bottom outlet in the tank permits release of water from the tank to flow into the bowl. A hinged flapper valve normally overlies the outlet so that the tank can be filled. Filling is accomplished to a predetermined level by means of an inlet valve which controls water inflow from a pressurized source. A float controls the valve to shut off the valve when the selected water level is reached. An overflow is connected to the tank outlet and stands upright next to the outlet. The overflow tube prevents the overfilling of the tank. The flapper valve is usually pivoted on the overflow tube.
Toilets are normally designed so that a more than adequate amount of water is delivered to the bowl at each flush to fully flush out the contents thereof. A considerable amount of water can be saved by individually adjusting the amount of flush water discharged in each toilet to accommodate for its individual design and installation. This is defined as a limited flush, wherein the minimum amount of water is employed to flush the toilet when there are solids present. Prior to the invention defined in the parent application, described above, there was no reliable structure available which provides for metering the release of water from the tank in a toilet, particularly with adjustability of the device to accommodate different toilet designs, and particularly for after-market installation in toilets of various shapes and characteristics.